This NHLBI PSO application requests funding for two years salary plus appropriate start up funds for a newly independent investigator whose research will complement the research underway in the Brigham &Women's Hospital's (BWH) Division of Sleep Medicine's research center. The research center's mission is to forge a path of discovery in sleep medicine and to train the next generation of leaders in academic sleep medicine. The Division has 31 faculty, 20 postdoctoral fellows and over 50 support staff, with the majority of effort spent on research. These research activities are funded by annual research grants of ~$11.8 million. The Division has a number of interacting research programs and cores, covering most aspects of sleep and circadian physiology, as well as sleep pathophysiology (mechanisms and therapy for the sleep disorders). However, we have identified an important area of research that is not currently well studied in our center, namely the interaction of the circadian system with disease. In particular, there is a critical gap in our understanding of the role of the circadian timing system in causing the very robust morning increase in adverse cardiovascular events (strokes, myocardial infarction, and sudden cardiac death) in vulnerable patient groups. We have identified a spectacular newly independent investigator whose research has moved in this direction and who is poised for promotion to Assistant Professor of Medicine. Should this P03 award be made, the institution is committed to providing appropriate research facilities for this individual, including use of the BWH Intensive Physiological Monitoring Unit in the Center for Clinical Investigation, a component of the Harvard Catalyst-Clinical and Translation Science Center. In addition, the investigator will fully utilize the many career development resources in the BWH Center for Faculty Development and Diversity. Together with close research and career mentorship from senior faculty in the Division's research center, we anticipate that a PSO award will lead to important discoveries concerning the role of the circadian system in the day/night pattern of adverse cardiovascular events, and greatly facilitate the career development of one of the most promising future leaders in academic sleep medicine. A PSO award will lead to important discoveries concerning the role of the circadian system in the very robust day/night pattern of adverse cardiovascular events, and greatly facilitate the career development of one of the most promising future leaders in academic sleep medicine.